1. Field of the Invention
The present invention relates to a solution treatment apparatus for performing solution treatment, for example, application of a resist, developing treatment after exposure, or the like, for a substrate such as, for example, a semiconductor wafer or a glass substrate for a liquid crystal display (LCD substrate), and a method therefor.
2. Description of the Related Art
The process of forming a resist pattern on a substrate that is one of manufacturing processes of a semiconductor device or an LCD substrate is performed by a series of processes of forming a resist film on the substrate, for example, a semiconductor wafer (hereinafter, referred to as a wafer), exposing the resist film to light using a photomask, and thereafter performing developing treatment so as to obtain a desired pattern. The series of processes have conventionally been performed by a coating and developing apparatus.
The coating and developing apparatus includes solution treatment units such as a coating unit for applying a resist solution, an anti-reflection film forming unit for applying a treatment solution for an anti-reflection film, and, to ensure a high throughput, a plurality of coating units and anti-reflection units are generally provided.
In the solution treatment unit, a cup body is provided in a manner to surround a spin chuck being a wafer holding portion, and treatments such as spin coating, shake-off drying, and side rinse are mainly performed in the unit. During the spin coating, the treatment solution dropped on the central portion of the wafer is spread in the radial direction of the wafer by centrifugal force, and therefore exhaust is performed by an exhaust pipe connected to the cup body to exhaust mist scattered by the spin. In this case, if the exhaust of mist is too strong, which may affect the thickness of the film on the wafer, and therefore the strength of the exhaust is determined depending on both of them.
During the shake-off drying and the side rinse, a solvent of the treatment solution is discharged while the wafer is being rotated or the treatment solution on the substrate is shaken off by rotation at a high speed, leading to an accordingly large amount of mist scattered, and therefore exhaust stronger than that during the spin coating may be required.
In this regard, Japanese Patent Application Laid-open No. 2000-156341 describes that exhaust pipes connected to cup bodies are joined together for common use at their midpoints, and opening/closing valves whose opening and closing are controlled by turning on or off are provided along the respective exhaust pipes upstream from the common point.